Is a quad in a triangular shape still bad for topology?
A good trig or quad topology depends on what you intend to use it for.
If you want to use blender modeling function (such as subsurf, snooth and other deformations) it is better to use quad since trig can make ugly/buggy result.

Some publications say trig can be usefull in animation or game but it depend what software you use. But usually quad is  better.